LEAD, S.D.?The Sanford Underground Research Facility in Lead has suspended operations deep underground, at least through Thursday morning, after a five-day storm dumped 8.75 inches of rain on the northern Black Hills. The suspension includes science operations at the facility?s 4,850-foot level.
?Safety is always our first consideration,? Laboratory Director Mike Headley. ?So far, our underground systems are performing as expected. However, an inspection team reported water backing up in some areas of upper levels.? Headley emphasized that the two main experiments on the 4850 Level are not in danger of flooding. ?We?ve temporarily prohibited access below the 1,850-foot level to give our water control systems a chance to catch up,? Headley said. ?Thursday morning crews will re-inspect several areas underground. If water is draining normally, we expect to resume normal operations.?
The two physics experiments on the 4850 Level are the Large Underground Xenon (LUX) experiment, which is looking for a mysterious substance called dark matter, and the Majorana Demonstrator experiment, which will search for a rare form of radioactive decay. The LUX detector is assembled and undergoing testing. Majorana is under construction. Researchers working on both experiments returned to the surface about noon today (Tuesday).
Sanford Lab Science Director Jaret Heise said the short suspension of access would not damage either experiment. ?We?re prepared for unusual events,? Heise said. ?Both experiments are safe and secure.?
The Sanford Lab is in the former Homestake gold mine, which includes 370 miles of tunnels and 14 shafts that reach all the way down to 8,000 feet underground. Water flows into the underground mostly through a large pit called the Open Cut, just off Main Street in Lead. Eventually runoff reaches the bottom of Homestake. A system of pumps removes water from that deep pool and pumps it back to the surface, where it is treated before being released to a local stream.
The current water level of the deep pool is just below 5,900 feet underground. Even if the deep pumps were turned off, it would take about a year for the water to reach experiments on the 4850 Level.